1. Field of the Invention
The present invention generally relates to a surgical instrument for applying purse string sutures to tissue and, more particularly, to a surgical instrument for applying purse string sutures to tubular tissue without the need for a surgeon to manually insert the suture needles into the instrument during the performance of surgery. Moreover, this invention relates to a purse string suture instrument provided with a pair of tissue clamping jaws which are adapted to firmly grip and shape the tissue into an appropriate configuration to be sutured and which capture the suture needles after the sutures are threaded into the tissue. Also, this invention relates to a purse string suture instrument which incorporates a knife blade for cutting the tissue adjacent to the purse string sutures threaded therein. Further, this invention concerns a purse string suture instrument provided with a tissue clamp which is applied to the tissue when the instrument is operated.
2. Description of the Prior Art
Purse string suture devices are known in the prior art which comprise a pair of serrated tissue clamping jaws provided with teeth for clamping the tissue to be sutured therebetween. Such devices include needle passages which extend through the teeth on each jaw for receiving a needle attached to a suture to be threaded through the tissue. In use, the tissue to be sutured is clamped between the jaws and the needle is manually passed through the needle passages in both jaws to thread the suture through the tissue. Thereafter, the jaws are opened and the purse string suture is tightened and wrapped to draw the tissue together. With this type of device, a considerable amount of manual effort and dexterity is required to accomplish the purse string suturing technique. Also, in such devices, it is difficult to control the flow of tissue between the teeth because an insufficient amount of space is provided to gather the tissue clamped by the jaws.
In the prior art, it has been proposed to provide automatic surgical instruments for applying the purse string sutures. For example, U.S. Pat. No. 4,915,107 discloses a purse string suture instrument in which a pair of needles attached to suture threads are driven through needle passages in the tissue clamping jaws by a pair of wires advanced simultaneously from rotatable drums. The tissue clamping jaws include teeth which are rectangular in configuration and separated by rectangular spaces. In use, it is desired that a sufficient amount of tissue be pinched into the spaces between the teeth to receive the needles and suture threads which are driven through the passages in the jaws. However, it appears that only a limited amount of tissue can be pinched into the path of the needles because of the rectangular configuration of the teeth and the rectangular spaces therebetween. Thus, it is possible that an insufficient amount of tissue may be gathered into the spaces between the teeth to properly perform the purse string suturing technique. Nor is any provision made to protect the sutures from damage as the needles are advanced through the passages in the teeth. Thus, the purse string sutures are exposed to possible damage or breakage as the sutures are drawn through the passages in the teeth. Also, no provision is made to capture the needles after being driven through the passages. Thus, after operating the instrument, the surgeon must manually retrieve the needles to locate the purse string sutures.
Accordingly, it is desirable to provide a surgical instrument for applying purse string sutures in which the tissue clamping jaws gather a sufficient amount of tissue into the spaces between the teeth to receive the purse string sutures. Also, it is desirable to provide a purse string suture instrument which operates automatically and captures the needles after advancement through the needle passages to allow the needles and sutures to be conveniently retrieved by the surgeon. Further, it is desirable to provide a purse string suture instrument which guards the purse string sutures against damage as the sutures are drawn through the passages in the teeth.
In addition, it is advantageous to provide a purse string suture instrument which incorporates a knife blade to sever the tissue adjacent to the purse string sutures threaded into the tissue. Additional advantages can be achieved by a purse string suture instrument provided with a tissue clamp which is applied to the tissue when the instrument is operated.